1. Field of the Invention
Exemplary aspects of the present invention relate to a belt device, a fixing device, and an image forming apparatus, and more particularly, to a belt device for conveying a recording medium and a fixing device and an image forming apparatus incorporating the belt device.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, or multifunction printers having at least one of copying, printing, scanning, and facsimile functions, typically form an image on a recording medium according to image data. Thus, for example, a charger uniformly charges a surface of an image carrier; an optical writer emits a light beam onto the charged surface of the image carrier to form an electrostatic latent image on the image carrier according to the image data; a development device supplies toner to the electrostatic latent image formed on the image carrier to render the electrostatic latent image visible as a toner image; the toner image is directly transferred from the image carrier onto a recording medium or is indirectly transferred from the image carrier onto a recording medium via an intermediate transfer member; a cleaner then cleans the surface of the image carrier after the toner image is transferred from the image carrier onto the recording medium; finally, a fixing device applies heat and pressure to the recording medium bearing the toner image to fix the toner image on the recording medium, thus forming the image on the recording medium.
The fixing device installed in such image forming apparatuses may include a flexible endless belt and an opposed pressing roller that apply heat and pressure to a recording medium bearing a toner image. For example, the pressing roller is pressed against the endless belt heated by a heater to form a fixing nip therebetween through which the recording medium bearing the toner image is conveyed. As the endless belt and the pressing roller rotate and convey the recording medium through the fixing nip, they apply heat and pressure to the recording medium, melting and fixing the toner image on the recording medium.
For example, the flexible endless belt is rotatably attached to a flange at each lateral end of the endless belt in the axial direction thereof in such a manner that the endless belt, as it rotates, slides over the outer circumferential surface of the flange. The flange is mounted on a frame of the fixing device, thus supporting the endless belt.
However, as the endless belt rotates for a long time, it may skew and its circumferential edge may strike and scratch the flange, scraping particles off the flange by frictional contact with the flange. The scraped particles may enter the slight gap between the inner circumferential surface of the endless belt and the outer circumferential surface of the flange, increasing friction between the flange and the endless belt sliding over the flange. As a result, the increased friction may increase rotation torque of the endless belt, destabilizing rotation of the endless belt.